Frequency multiplying apparatus



June 11, 1946. w, o, BENNETT, JR 2,402,012

FREQUENCY MULTIPLYING APPARATUS I Original Filed June 17, 1941 THYRA TYPE TUBE AMPLIFIERS AMPUFER a PULSE PRODUCER 6 I 5 INVENTOR.

WILLIAM O. BENNETT, JR.

Patented June 11, 1946 2,402,012 7 v FREQUENCY MULTIPLYING APPARATUS William Ogle Bennett, J12, Lancaster Township,

Lancaster County, Pa.., assignor to Hamilton, Watch Company, Lancaster, Pa.

Original application June 17 1941, Serial No.

398,633. Divided and this application November 20, 1943, Serial No. 511,032

2 Claims.

This invention is directed to a method and apparatus of producing a stabilized alternating current from the sounds of an operating timepiece and is a division of Ser. No. 398,633, filed June 1'7, 1941, for Measurin devices.

In using the operating sounds of a timepiece to produce an electric current to run a motor whose speed can be compared with that of a motor operated on standard frequency current, there has been the difficulty of obtaining an alternating current which is stabilized and yet the frequency of which follows the rate at which the timepiece is ticking.

It is the purpose of this invention to provide an apparatus and method by which the sounds of a timepiece are changed to alternating current, the frequency of which is a multiple of the ticks of the timepiece being tested.

It is a further object of the present invention to provide a mechanical vibrator having a natural frequency and to either retard or accelerate the frequency by imposing impulses on the mechanical vibrator which will cause the vibrator to assume the frequency or a multiple thereof of the operating sounds of the timepiece being tested.

It is a further object of the present invention to provide new and useful improvements in the field of electric frequency current measurement and timepiece rate testing device.

It is a further object'of the present invention to provide means whereby the sounds of a timepiece may-be changed to electrical impulses, of such a frequency in nature as to permit a quick, accurate and simple determination of the rate of the timepiece by stabilizing the vibrating period of a mechanical vibrator in accordance with the electrical impulses produced by the timepiece.

It is a further object of the present invention to provide a mechanical vibrator carrying an adjustable weight to allow the vibrator to be adjusted to a desired natural frequency and to provide means to allow the mechanical vibrator to be readily driven off this natural frequency making it either slower or faster in accordance with a multiple of the frequency of the operating sound of timepiece.

It is a further object of the present invention to provide electrical means for governing the rate of a mechanical vibrator and to produce by means of the motion of said mechanical vibrator an alternating current, the frequency of which is a multiple of the operating sounds of a timepiece.

The invention is illustrated in the accompanying drawing in which the figure illustrated shows a. diagrammatic view of the invention. In the drawing a microphone l is shown for receiving the operating sounds of a timepiece to be tested. Connected to the microphone is an amplifying unit 2 and to the amplifying unit a Thyratron tube 3. The output of the tube 3 is then made to operate a vibrating reed 4. The output of this reed is picked up and passed through an ampliher and direct pulse producer 5 whose output, preferably 30 pulses per second, is in turn made to operate a watch motor 6, thus the watch motor is operated at a speeddepending upon the frequency of the sounds or ticks of the timepiece being tested.

The sound vibrations which originate in the socalled tick and took of a watch or timepiece are not in all cases produced at regularly spaced intervals and therefore the electrical impulses which are formed with these sounds are picked up by microphone are not necessarily produced at exactly regular'equally spaced intervals. In order to accomplish satisfactory measurement of watch rates by operating a synchronous motor from a frequency derived from the ticks it isessential'that the electrical impulses comprising the motor driving frequency be regular and produced at essentially equally spaced intervals. The stabilization and production of the necessary alternating current is accomplished by means of the vibrating reed system 4 which has a vibrating arm 1 anchored at 8 comprising a relatively thin portion 9 and carrying adjustable weight ll) which slides on the arm 1 and is held in adjusted position by the thumb screw II.

The frequency is carefully calculated to a small multiple of the frequency of electrical impulses derived from the sounds of an accurately operating timepiece. The vibrating reed, however, is so formed as to be readily driven on" of this natural vibrating frequency that a variation in the frequency of the electrical impulses in the output of the microphone will control the vibration of the reed and keep it in step with the frequency of the sounds of the watch. It is, therefore, seen that the sounds of the watch control the vibration of the reed and the ultimate result is that the watch sounds are stabilized by means of the rapidly vibrating reed and yet the reed has a period which is a multiple of the watch sounds. Referring again to the drawing the output of the thyratron circuit in block 3 periodically energizes an electro-magnet l2 and since the vibrating arm I is anchored at its end 8 is free to vibrate through the remainder of its extent and since the free end 13 of the vibrating arm 1 is of magnetic material and is in its position of rest located at a point slightly to one side of the core I4 of the electro-magnet l2, when the electro-magnet is energized the magnetic force will either push or pull the vibrating arm I and so start the arm to moving. The vibrating arm 1 carries near its upper end a permanent magnet; l5 which moves with the arm' during its vibration. The ends of the magnet [5 pass through pick-up coils l6 and the movement of the permanent magnet through these coilsl produce electrical impulses in step with the vibration of the arm and consequently the sounds: of, the watch and these electrical impulses thus produced are passed to the amplifier and pulse producer 5'and then to the watch motor 6.

The pulse produces and amplifier" operates tochange the frequency of 15 cycles to cycles. This is accomplished by means of a full wave rectifier and an amplifier torpeak the impulses. The apparatus here used is purchased and any means of accomplishing the result may be used.

The. electrical impulses coming. from block 3' into the magnet. 12, emanating from watch sounds, are not always equally spaced but by impressing these. impulses on the vibrating reed the resulting impulses emanating from the pick-up coll l6 are equally spaced and the frequency is a multiple of the frequency of the watch sounds. The. operation of the vibrating reed might be compared to the operation of a; balance wheel in a watch as the reed vibrates because of its inertia and receives intermediate energizations from the electro-magnet I! which maintain this vibration and which also govern the vibration. The output of the vibrating reed, however,, is uniform since the effect. of the watch governed impulses is gradual and only results in an acceleration or delaying action of't'he natural vibration ofthe reed.

In order to. give the reed; the greatest possible energization the free end, I3 is. placed. very close to the. electro-magnet. l8 and likewise. inorder. to. give the permanentmagnet. lithe. greatest mo.ve.- ment. through the pick-up. coils, [6,. they are. also.

placed adjacent the free end. This arrangement brings the coils of the electro-magnet I2 into relatively close position to the pick-up coils I6 so that there is an electrical linkage between the electro-magnet I2 and the pick-up coils l6 which is. undesirable since if unchecked, it would introduceirregularities into the output of the vibrating arm system. Accordingly, a balance circuit is set up with a take off from the coil where the electro-magnet l2 which directly feeds sufficient current into the pick-up coils IE to offset the current in the coils resulting from the above-mentioned undesirable linkage. This balancing effect is made adjustable through variable rheostats l1.

What I claim is:

l. A frequency multiplying apparatus comprisinga mechanical vibrator, an adjustable weight carried on said vibrator for changing the frequency of said vibrator, a source of electrical impulses, an electromagnet actuated by said im-- pulses, the output of said electromagnet being imposed upon the mechanical vibrator to cause said mechanical vibrator to vibrate with a frequency which is a multiple of said electrical impulses, a permanent magnet extending through and carried by said mechanical vibrator, pickup coils arranged adjacent said mechanical vibrator and within the field of said permanent magnet, whereby the movement of. said permanent magnet through the pickup coils creates an alternating, current equal in. frequency to the vibrations of said mechanical vibrator.

2. A vibrating reed used in conjunction with a timepiece rate testing device comprising a single vibrating element, means actuated by the sounds of a timepiece for driving said vibrating element at a frequency which is a multiple of said timepiece sounds, a pair. of solenoids, a permanent magnet extending through and carried by said vibrating reed. adapted to move within said solenoids to produce an alternating current equal in frequency to the frequency of said reed.

WILLIAM OGLE BENNETT, J a. 

